Zoladz Jerzy A, Szkutnik Zbigniew, Duda Krzysztof, Majerczak Joanna, Korzeniewski Bernard
Department of Muscle Physiology, AWF-Kraków, Al. Jana Pawla II 78, 31-571 Kraków, Poland.
J Appl Physiol (1985). 2005 Mar;98(3):895-904. doi: 10.1152/japplphysiol.01194.2003. Epub 2004 Oct 29.
The present study investigated the effect of preexercise metabolic alkalosis on the primary component of oxygen uptake (Vo(2)) kinetics, characterized by tau(1). Seven healthy physically active nonsmoking men, aged 22.4 +/- 1.8 (mean +/- SD) yr, maximum Vo(2) (Vo(2 max)) 50.4 +/- 4 ml.min(-1).kg(-1), performed two bouts of cycling, corresponding to 40 and 87% of Vo(2 max), lasting 6 min each, separated by a 20-min pause, once as a control study and a few days later at approximately 90 min after ingestion of 3 mmol/kg body wt of NaHCO(3). Blood samples for measurements of bicarbonate concentration and hydrogen ion concentration were taken from antecubital vein via catheter. Pulmonary Vo(2) was measured continuously breath by breath. The values of tau(1) were calculated by using six various approaches published in the literature. Preexercise level of bicarbonate concentration after ingestion of NaHCO(3) was significantly elevated (P < 0.01) compared with the control study (28.96 +/- 2.11 vs. 24.84 +/- 1.18 mmol/l; P < 0.01), and [H(+)] was significantly (P < 0.01) reduced (42.79 +/- 3.38 nmol/l vs. 46.44 +/- 3.51 nmol/l). This shift (P < 0.01) was also present during both bouts of exercise. During cycling at 40% of Vo(2 max), no significant effect of the preexercise alkalosis on the magnitude of tau(1) was found. However, during cycling at 87% of Vo(2 max), the tau(1) calculated by all six approaches was significantly (P < 0.05) reduced, compared with the control study. The tau(1) calculated as in Borrani et al. (Borrani F, Candau R, Millet GY, Perrey S, Fuchsloscher J, and Rouillon JD. J Appl Physiol 90: 2212-2220, 2001) was reduced on average by 7.9 +/- 2.6 s, which was significantly different from zero with both the Student's t-test (P = 0.011) and the Wilcoxon's signed-ranks test (P = 0.014).
本研究调查了运动前代谢性碱中毒对以τ₁为特征的摄氧量（V̇O₂）动力学主要成分的影响。七名健康、有体育活动习惯且不吸烟的男性，年龄为22.4±1.8（均值±标准差）岁，最大摄氧量（V̇O₂max）为50.4±4 ml·min⁻¹·kg⁻¹，进行了两轮骑行，强度分别相当于V̇O₂max的40%和87%，每次持续6分钟，中间间隔20分钟。一轮作为对照研究，几天后在摄入3 mmol/kg体重的NaHCO₃约90分钟后进行另一轮。通过导管从前臂静脉采集血样以测量碳酸氢盐浓度和氢离子浓度。逐 breath 连续测量肺V̇O₂。τ₁值通过文献中发表的六种不同方法计算得出。与对照研究相比，摄入NaHCO₃后运动前的碳酸氢盐浓度显著升高（P<0.01）（28.96±2.11 vs. 24.84±1.18 mmol/L；P<0.01），而[H⁺]显著降低（P<0.01）（42.79±3.38 nmol/L vs. 46.44±3.51 nmol/L）。这种变化（P<0.01）在两轮运动期间也存在。在相当于V̇O₂max 40%的骑行过程中，未发现运动前碱中毒对τ₁大小有显著影响。然而，在相当于V̇O₂max 87%的骑行过程中，与对照研究相比，通过所有六种方法计算得出的τ₁均显著降低（P<0.05）。按照Borrani等人（Borrani F, Candau R, Millet GY, Perrey S, Fuchsloscher J, and Rouillon JD. J Appl Physiol �0: 2212 - 2220, 2001）的方法计算得出的τ₁平均降低了7.9±2.6秒，通过Student's t检验（P = 0.011）和Wilcoxon符号秩检验（P = 0.014），该降低值与零均有显著差异。
